CONTROL OF ODONTJUA BY DDT and BHC INSECTICIDES

A paper on the subject of grass-grub and subterranean caterpillar control was read at the -1950 Grassland Conference at Invercargill; the work has been continued and the Ashburton Station has issued a pamphlet giving more definite recommendations than in the previous paper. The present paper is confined to control ,of grass-grubs, but the same treatment will automatically kill porina (subterranean caterpillar or Oxycanus). Though control recommendations are included and will be published in this paper, it is intended to confine remarks to factors that can prevent good control by DDT and BHC. The recommendations are :1. For general grazing land or where a pasture life of not more than 2 years is required whew grass-grub alone is present use either: (a) llb of 100 per cent parapara isomer DDT per acre or its equivalent at lower percentages, e.g., 21b of 50 per cent ppi ; 41b